Isoorientin-6"-O-glucoside, a water-soluble antioxidant isolated from Gentiana arisanensis.
The antioxidant activities of isoorientin-6"-O-glucoside were studied using various models. Isoorientin-6"-O-glucoside was more potent than Trolox, probucol and butylated hydroxytoluene (BHT) in reducing the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). It also scavenged superoxide anion, peroxyl and hydroxyl radicals that were generated by xanthine/xanthine oxidase, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and Fe3+-ascorbate-EDTA-H2O2 system, respectively. The IC50 value, stoichiometry factor and second-order rate constant were 9.0+/-0.8 microM, 1.8+/-0.1 and 2.6 X 10(10) M(-1) s(-1) for superoxide generation, peroxyl and hydroxyl radicals. However, isoorientin-6"-O-glucoside did not inhibit xanthine oxidase activity or scavenge hydrogen peroxide (H2O2), carbon radical or 2,2'-azobis(2,4-dimethyl-valeronitrile) (AMVN)-derived peroxyl radical in hexane. Isoorientin-6"-O-glucoside inhibited Cu2+-induced oxidation of human low-density lipoprotein (LDL) as measured by fluorescence intensity, thiobarbituric acid-reactive substance formation and electrophoretic mobility. Since isoorientin-6"-O-glucoside did not possess pro-oxidant activity, it may be an effective water-soluble antioxidant that can prevent LDL against oxidation.
Ko
F N
FN
Pharmacological Institute, College of Medicine, National Taiwan University, Taipei.
Chu
C C
CC
Lin
C N
CN
Chang
C C
CC
Teng
C M
CM
D000975:Antioxidants / Q000302:isolation & purification* / Q000494:pharmacology; D015764:Bepridil / Q000031:analogs & derivatives / Q000378:metabolism; D001713:Biphenyl Compounds; D003300:Copper / Q000494:pharmacology; D003855:Deoxyribose / Q000378:metabolism; D005419:Flavonoids / Q000302:isolation & purification / Q000494:pharmacology*; D005453:Fluorescence; D016166:Free Radical Scavengers / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism; D005960:Glucosides / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D015227:Lipid Peroxidation / Q000187:drug effects; D008077:Lipoproteins, LDL / Q000378:metabolism; D047311:Luteolin; D015394:Molecular Structure; D010851:Picrates; D010944:Plants / Q000737:chemistry*; D013481:Superoxides / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis
D000975:Antioxidants; D001713:Biphenyl Compounds; D005419:Flavonoids; D016166:Free Radical Scavengers; D005609:Free Radicals; D005960:Glucosides; C110612:Isoorientin-6-O-glucoside; D008077:Lipoproteins, LDL; D010851:Picrates; D017392:Thiobarbituric Acid Reactive Substances; D013481:Superoxides; D003855:Deoxyribose; D015764:Bepridil; D003300:Copper; C057912:homoorientin; C004931:1,1-diphenyl-2-picrylhydrazyl; D047311:Luteolin